Step 3a: Remove Radiator

I am back again, tired of writing on the book and needing a break.  If I am to reach my goal of having the engine rebuilt by the time school starts in the fall I have to get serious about pulling the engine from Green for a rebuild.

The service manual stated that the first order of business is to remove the radiator.  Actually, it says the first step is to drain the fluids; the second is to unbolt and remove the hood, but I don’t have anywhere to store it right now, so I plan to work under it until whatever else can be done first is done.  When the engine is ready to lift, then it will come off.

So this starts with step 3 (and I’ll number things to follow the service manual).  Thankfully removing a radiator is a simple function. Unfortunately, because this is such a straightforward job there isn’t much interesting that can be said about the process.

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The radiator in place.

Obviously the first step is to remove the upper and lower hoses.  Hose clamps are straightforward:  a flat screwdriver loosens the clamp.  That part was simple, but the ends of both hoses have not been moved in quite awhile. Both required a bit of prying to get them off the nipples.

The wiring on Green is absolutely original (and will absolutely be replaced), but even the purest motorhead knows that hoses are almost never original on a vehicle this old.  They take far more punishment from the heating and cooling every time the motor is started than wiring ever does. I was a bit surprised, however, to notice that the lower hose had been replaced rather more recently than I had anticipated.  Beneath the clamp part of the paper label was clearly readable.  Though the hoses will certainly be replaced in the rebuild and these will be tossed, I plan to hold onto everything until I finish, just in case I need to consult “how did they do that” on something.

The radiator is secured to the back of the radiator frame by three bolts up either side.  The frame is a welded and bent C-channel.  The bolts pass through the flange on the radiator and into square nuts that sit in a socket that wraps around the sides which in turn seems to be welded to the frame.  I forgot to photograph those, but I get the impression that one could pry the folded steel leaves from around the nuts and pull them out; perhaps it was to simplify replacement if the threads stripped.

The bolts thread through from the engine compartment.  They are identical on both sides so only one is shown here.  They were not seized at all, though they undoubtedly have not been removed since the original 216ci motor was replaced, some time after 1955.

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Though they were not hard to remove and would have gone back in place with a bit of effort, I still gave the threads of each bolt a good brushing with a brass brush, then a quick coating of WD-40 as an anti-rust, anti-corrosion treatment.  Here are a pair of before and after shots of one bolt, though frankly it doesn’t show much.

I was a bit surprised to find that the bolts were mismatched.  The one in this image is probably original, with an integrated washer cast onto the head.  At least two of the bolts were just . . . bolts, with regular washers.

It was impossible to photograph myself while lifting the radiator, so you’ll have to trust me that I did it all by myself.  I put back the drain plug, though it is clear that the fiber-core freeze plug will eventually have to be replaced.

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With the radiator out I could clear out the decades of decomposed detritus that are  in the frame, which is a shallow U.  This is the dust of hay fields, decayed leaves and seeds from the orchard, water from the springs, and who knows what other parts of Hilltop and the farm.  I have to say I got a bit nostalgic as I scooped it out, because I was literally touching my childhood again—not too nostalgic, though; I did toss it.

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With the radiator out, it was a simple matter to remove the fan belt.  This, it turns out, had also been replaced at some time in the past.  The original belt configuration was to have one belt drive the fan from the power train, then to have a second belt from the fan drive the generator.   Though there are two channels on the fan pulley, it is clear from the shape and size of the belt that it was driving both the fan and the generator from the drive train.  It is not an optimal arrangement and might explain why it could be so hard to start Green sometimes—the three-corner shape does not have enough contact with the pulley to drive the generator effectively.

Removing the radiator was fairly simple.  Next step is to unbolt and pull the radiator frame.

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Blinded by the light.

Sorry for the delay in posting.  This fall has been a cycle of stress and activity. Green therapy has taken a lower priority—like, not at all.

But, the other day I was moving something in the walkway between Green and the workbench and clipped the front of the radiator pretty well.  That set me thinking that before I go too far, it might be well to deal with the headlights and running lights.  Both of them are glass, not plastic, and are pretty exposed targets.  At some point—hopefully sooner than later—I need to pull a shop crane in place to lift the motor from the engine compartment, and I run the risk of something smacking the glass headlights.

Thankfully, this is an old truck, so nearly everything requires nothing more complex than a flat screwdriver.  When Green was assembled, a Phillips screwdriver was fairly radical automotive design.  None of these star bits, Allen bits, retaining clips and other modern inconveniences.  If it didn’t require a screw, it was welded or bolted–end of story.  So, fishing out a screwdriver, I went at the retaining frames to see if I could get things out before something broke.  There was a single screw visible at the bottom of the ring; the top is held in place by a tongue in a slot.  Simple.

For the headlights, you can see here that the chrome bezel came off easily.  Behind it is two other rings.  The one on the front holds the headlamp in place and sets the direction of the headlight in relation to the road.  One side has a spring, the other a screw to control left-right repositioning.  Once that was removed the headlight itself came right out.  So did the miscellaneous wasp nests.

The inner ring is the housing, though not a reflector; the back of the lamp itself is the reflector.  Modern headlights are composites.  To change one in our Chevy Sonic, one unclips the assembly from the back of the headlight assembly, pulls out the lamp assembly, swaps the bulb, and clips everything back together.  The assembly fits into the ABS plastic reflector, which is fronted by clear polycarbonate.

In Green the entire headlight is a lightbulb itself.  It has a three-pronged plug into the connector, but the connector is merely shoved behind the lightbulb.  Nothing is sealed, and the wires are simply knotted so that they are not pulled out of the housing in the front fender.  Talk about elegantly simple, but weatherproof?  No.

The front running lights are a little different.  Each one has a glass bezel that is held onto the metal reflector, between which sits a rubber gasket to close off the whole light to the elements.  You can see here that the gasket is essentially no more.  Years of sitting out in the heating-cooling weather cycle has made it cockled and brittle.  Behind the bezel sits a real glass bulb with an amber coating, but again, with the connector wires merely shoved through the back.

So there–I’ve more or less carefully removed the glass that could be broken as I begin work on the engine. If this was a full restoration I’d probably paint the headlight sockets when the fenders were painted, but I’ll have to think about that.  Green has to have working lights, but the goal is merely to bring him back into running order good enough to pass a state inspection.  Paint behind the headlights would be optional.

 

Driving Cornwall, Walking London.

The blog has experienced a bit of suspension as I made a trip to England and France this month. I was the historian (color commentary) for the first Community on the Go trip abroad, an excursion to London, Normandy, and Paris to see the sites of Operation Overlord, the invasion of France during WWII.

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Other than these few pictures I’ll leave recounting the trip for another venue, but since this is a blog about a truck, there is room for automotive comment.

I took the opportunity to arrive a few days early, hired a car, and drove out to the end of Cornwall and the site of the family’s origin.

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The trusty steed, Audi.

I picked up a car at Heathrow International and had to adapt immediately to driving on the right side of the vehicle and left side of the road.  I talked to myself nearly constantly for three days, reminding myself to turn into the left lane, to look to the right at intersections, and to interpret road and street signs.

The drive from London across Devon and through Cornwall was spectacular, even if it was November. The landscape was livid green, the kind of green that North America gets only in spring.

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Southwest along the M5, outside of Taunton

Once I got off the M4 and M5, the driving got positively interesting.  Google Maps is a great tool, but it doesn’t think “this is a ridiculously narrow, unmarked lane in the middle of nowhere” for you.  The plotted route eventually took me down farm roads through the hedgerow country that were, quite frankly, a little nerve wracking. The roads are narrow enough that I regularly drove with the shrubbery leaving wet traces down the side of the car and me worrying about the liability inherent in rental agreements. These are two-way roads in name only; the only way to drive them is to employ the car-length wide spots in these roads, the only points at which two vehicles can pass each other without a head-on collision.  I did that fairly frequently and occasionally backed up to the closest one after coming nose-to-nose with another driver.  My host said that proves I am not a local—locals just sit and stare at each other, waiting for the other to move back.

The towns were not much better. I guess that comes from having building sites laid out in the days when distance and speed was measured on a walking scale, well before automobiles could be even imagined. Now that we sit in our little wheeled boxes, the physical setting and needsi to see around the corners historic buildings makes for quite a challenge. The lack of walkways is unsettling, but then traffic is not heavy in St Keverne.

I made it through the countryside and even through urban driving in Plymouth.  THAT was an experience I won’t forget. I was busy enough driving on the right—er, correct—side of the road and juggling all the variables while trying to navigate that I did not take the opportunity for a single photograph.  For someone used to straight streets, right-angle intersections, and street signs posted close to the road, it was a real challenge.

But, after three days of driving entirely on my own I made it back to London, without damage and without incident.

I’d love to go back.  It was spectacular trip, but I have no more trips planned.  This year the task is to get back into the Green Truck.

Radiator drain.

Apologies for being uncommunicative.  This fall has been a ceaseless round of obligations.  I’ve had no time at all to work on Green, and really not much time to do much else.  Won’t bore you with those details (partly because they involve planning for a trip to London and Paris–no, not London KY or Paris TN; more on that in a couple of weeks).

One thing was a head-slapper as I worked on disconnecting everything to pull the engine:  “oh yeah–I forgot to drain the radiator.”

So, here is the drain plug.  The white pokey-out thing in the middle seems to be a soft fiberglass of some sort.  It is original and has taken lot of abuse from rocks, alfalfa, orchard grass, sagebrush, and anything else that could get up and bang on the frame.

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The plug came out without a hitch–but so did the coolant.  As you can see, I got a shower.

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The good news was that I was pleasantly surprised.  The transmission fluid had reverted nearly to tar sand, but the coolant looked clear.  I expected the coolant to match—a viscous sludge, full of rust and other ickiness.

 

Removing the radiator grille upper and lower baffles.

Pulling the engine requires a lot of advance work.  The shop manual lists the steps, but not piece by piece–just action by action.  Obviously removing the radiator means removing everything in front of it, including the grille and fenders.  So I start here.

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When the hood is opened the first thing visible is this nose, the upper grille baffle, a plate that covers the radiator. It probably isn’t absolutely necessary structurally, but as you can see, the hood latch sits in the middle. Its real purpose is to direct air moving from the grill through the radiator just behind it.  There are places for fifteen bolts, but one is missing (not quite visible on steep slope to the left).  Two rubber bumpers (left one missing, the right one is the round black thing on the right) provide shock absorption for the hood as it closes and presumably keep it from rattling too badly when driving.  I don’t remember a time when Green didn’t rattle, so the missing bumper is no loss.

There are at least two different sizes of bolts holding the baffle onto the radiator frame, each with a lock washer.  The ones across the top also hold the clips through which pass the cable of wires for the passenger-side headlamp and running light.  These bolts thread into either a tapped hole in the frame, or if into sheet metal, into a nut that is mounted on the opposite side of the mated piece (don’t have any pictures of those).

Unfortunately, I found out immediately that both bolts in the front corners of the baffle next to the fenders were rusted solidly in place.  The one on the left snapped cleanly with hardly any effort.  Despite a generous helping of WD-40 penetrating oil and smacking the driver’s side one with a drift punch and hammer to loosen things, that head also snapped off with very little effort, leaving me a new project to extract them.  I suspect that they were rusted deeply in place because rainwater and snow-melt would run through here on its gravity-mandated race to the ground.  The other bolts were similarly difficult, but one I got out. The other was also beheaded. Fortunately, I was able to reach a hand through the grille and up under the baffle to get out the bolt body in the image on the right.  It was one of the front just in front of the corner of the latch.

I was a bit surprised to find out that the bolts with smaller heads are in fact sheet-metal screws, which require their own type of nut, a clip which slides onto a punched hole in the body panel’s sheet metal. The clips provide an effective way to anchor the screw and can be replaced without risking damage to the sheet metal itself.

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Here is the upper radiator baffle from underneath. Comparing the top image to the one here, it is clear that the hood latch bolts onto the underside of the upper grille baffle.  I’ll deal with that later; it works fine and there is no reason to tear into it.

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2017sep09-19You can see that some of the bolts go into the grille frame assembly.  The two support rods were not too much support—neither was bolted onto the bottom baffle.  One had a bolt in place but did not actually go through the hole for it; the other simply didn’t have a bolt, so both were hanging loose.  I was surprised to see that the bolt head had a cast-in part number:  “W1” over a “C”.

So here is the front of Green with the upper grille baffle removed. In the picture above, the lower grille baffle is visible below and in front of the radiator.  It bolts on from the bottom and does not promise too much excitement, so I’ll skip documenting its removal unless something interesting happens in the process.

 

What I did find, atop the bottom baffle and behind the grille, was a couple handfuls of dirt and decaying plant matter (mostly seeds and leaves from my uncle’s barnyard).  Nostalgia strikes you over the most curious things, in this case it was a handful of dirt.  Some of that grit undoubtedly blew in there while I was driving Green regularly.  It is from the ravine where I used Green to haul sprinkler pipes. It is the blowing dust on the gravel road back from the west fields with a load of baled hay.  It is from the orchard where I loaded crates of apples.  From the north corral where we backed up to the barn to unload into the hay loft.  A few grains are from the small two-car parking lot on the south side of grandma’s house beyond the lawn and hedge, where Green spent most of its time parked, if it wasn’t in the orchard, staring into the sunset.  That is the Great Basin dirt and dust of my childhood and young adulthood.  I am terribly sentimental and it made me think and remember as I was sweeping up—but not so sentimental that I kept it.  There is a limit, y’know, even for me.

2017sep09-20I’m taking Green apart piece by piece, and there are a lot of pieces to keep straight. Just for the record, all of these fasteners, including broken ones, go in groups into one-quart freezer bags.  I write the part name and assembly manual sheet number onto a piece of paper and stick it in there as well so that I can both find them easily and reuse the unmarked bags as the project goes along.  The bagged stuff is stored in the large drawers of the tool cabinet; the larger parts go into the bed of the truck.  Matching parts like the support rods get zip-tied together. And I document everything photographically before it gets removed, so I know what should be there when I try to put back together the puzzle.  Don’t trust my memory.

 

 

 

Decision point—The engine.

A few eager friends have pressured me to put some new oil into the Green Truck, re-mount the generator, patch up the wiring, and fire it up.  Tempting, I’ll admit.  These old motors are simple, tough, and very forgiving.  I’d like to get Green running, but I also want to do it right so as not to cause damage, because I have no idea what sitting motionless for 32 years has done to the components.

So, I have reached a decision:  I have to rebuild the engine.  That will mean pulling it out and taking it completely apart.  For those of you reading the blog, it should be good fun to see if all the parts go together again.

I plan to start a new page on the rebuild cleverly titled “Engine rebuild.”  You’ll see the first entries on it soon.  To get started I borrowed a two-ton mobile engine hoist from a neighbor who has a real auto hoist in his garage.  He hasn’t needed this one in six or seven years and said I could keep it as long as needed.  That sealed the deal for me, so the removal and complete rebuild of the old inline or I-6 “stovebolt” engine will be the subject of the posts through the fall and winter. By spring perhaps the engine will be ready to go back in place. I hope.  My goal is to have Green at least in safe running condition again by the next local auto show.

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The first priority as I work will be to produce very complete photodocumentation of just what is connected to what else.  Anything that comes off will be labeled and stored for replacement.  Well, almost everything; eventually the entire electrical harness, the wiring, will have to be replaced.  I am looking for some braided-sleeve reproduction wire suitable to a truck of this type.

So, stay tuned; the fun is just beginning.

 

Brake master cylinder–IV. Remount

So—the tiny bits of metal, the lock washers, are rather important to keeping the brakes actually on the truck. That’s why the previous post on lock-washer quality was worth the digression.

See, the twin bolts that pass through the body of the master cylinder, through the mount on the frame, and into threaded holes in a bar on the other side, are held tightly in place by a lock washer.  A lock washer, for those who don’t know (or didn’t read the previous post), is essentially a nearly flat spring—a washer with a slit on one side and twisted slightly. When a bolt or nut is cinched down on a lock washer, the spring is pushed flat but pushes back against the head of the bolt to keep tension on it and prevent it loosening from the vibrations incident to driving.

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The master cylinder body on the bench, with the mounting bolts and lock washers in place

The other working part is the mounting bar, a simple piece of steel with threaded holes in either end that acts like a double nut.  Normally it would have just gone back on without a second glance, but in cleaning up the pieces after removing the master cylinder body a few months back I noticed that there was something stamped on the outside of the bar.  Aha!  The topic of another blog post!—and then I decided to just put it all together with the master cylinder.

To clean it up I used an old trick from woodworking:  a three-dollar jug of acetic acid—plain white vinegar.  This vinegar, however, I concentrated from 5% acidity to about 12% by simply setting the jug in the deep-freezer.  The water freezes but not the acid, so simply pouring the not-frozen liquid into another container leaves a lattice of ice in the jug.  Once that melts out, the concentrated acid goes back into the vinegar jug—properly marked, of course.

To clear the rust off the base metal I poured a bit onto a paper towel and then set the bar face down on it for about half an hour.  A few quick strokes with the trusty wire brush revealled that the rust is not superficial and wouldn’t come off, despite my clever application of acetic acid.  Oh well.

The stamp is nearly impossible to make out, but across the top of the circle can just be made out “MADE IN USA”.  Right in the center is a four-digit number that I cannot quite read (probably a serial number for the part), and below that “DETROIT”.  I’ll keep looking to see if I can find out what the serial number was.

Re-mounting the brake master cylinder itself was no problem.  Here are shots of the mounting sequence, from cleared location to reattaching the brake line.

However, Green still does not have brakes.  Why?  Because while the cylinder has been rebuilt, the brake pedal has not yet been reattached and of course there is no brake fluid in the line. The rest of the brake system first needs to be checked for leaks, the wheel (slave) cylinders checked and perhaps honed. At least two springs need to be checked and cleaned or replaced. There is still lots to be done, but here is a visual before-and-after comparison.

Things do look a bit better, don’t they?

 

Brake master cylinder–III. A digression on lock washers.

I almost rolled this post into the remount, but the more I thought about it the more I decided it provided an opportunity to talk about a picky automotive detail that is near and dear to my heart.  Maybe it will do someone good.

Years ago I worked at the only big-box retail store that Anderson Lumber Company ever established.  Anderson was a century-old, family-owned regional business that was finally steamrolled in the corporate retail-chain expansions of the 1990s.  The sixty-location corporation could not compete with the massive national retailers, specifically Home Depot and Lowe’s, nor in the building supply industry niche dominated in the West by Burton Lumber.

Anyway, my job was building materials generally and specifically fasteners—nails, screws, nuts, rivets, washers, and bolts of all types.  I hated the job but actually loved what I handled.  People brought me puzzles all day long and I had a couple of thousand puzzle pieces to choose from.  In the process I learned more about holding things together than most real people can imagine.  That all came back this week as I got ready to re-mount the master cylinder.

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The two split washers–one literally split, but both will be replaced

The problem is that when the master cylinder was removed, one of the lock washers came off in pieces and the other one has a stress fracture on one side.  It won’t last. The picture here is from the earlier posting where the the cylinder was removed. I’ve seen and handled a lot of washers in my day, but to my practiced eye I face a replacement problem here.

First some background. Off-the-shelf steel fasteners with imperial dimensions (inches, etc.) like bolts, nuts, and washers, come in three grades. Grade 2 is soft, bolt-your-playhouse-together-quality steel.  It is fine for general construction that will not be subject to much stress or torque.  Grade 5 bolts are made of a much harder steel.  The bolts have three hash marks on the heads and the matching nuts and washers have a different color coating on the steel for visual identification.  These are for installations that take stress regularly, like stationary production machinery.  Grade 8 hardware is of very hard steel made specifically for machinery where failure is disastrous, like automobiles and construction equipment—basically, anything that carries people. Those bolts have six hash marks on the head and usually have an anodic coating to resist corrosion.  You want to mount a snow blade onto the front of your pickup? You use grade-8 bolts and nothing else.

Took a reluctant Son Four with me to experience the thrill of hunting lock washer replacements. None of the auto parts stores carried a washer which matched what came off of Green.  I was afraid of that, but one always asks first.

So from experience I knew I had two options.  The pictures show side and top views of the three 7/16-inch washers together.  On the left and sort of a pale green is a standard grade-8 lock washer, with Green’s original equipment in the center, and a special kind of lock washer called a high collar washer on the right.  There are clear differences and therefore trade-offs in the two options, and that’s really the subject of this post because using the right components—even these two bits of steel—is actually a critical matter and worth the not-original-equipment compromise.

Compared together it is pretty clear that the washers taken off of Green, produced in the 1940s, do not match the industry-standard stuff commercially available today.  The grade-8 washer matches the OD or outside diameter of the original washer, but the material is nowhere near as thick.  The high-collar washer has the thickness of the original, but not the OD to match.  Since there was no way to get a replica of the original, and because Green has existed as a patched-up workhorse anyway, despite my desire to maintain the original equipment, swapping out the washer is appropriate.  I opted for maintaining the OD, which meant a pair of the $0.23 grade-8 washers.  No doubt Grandpa would have done the same.

Sorry for that uninteresting automotive digression; just wanted to show off my extensive working knowledge of picky industrial-standard details.  I’ll say more about lock-washer mechanics in the next post.

 

Brake master cylinder rebuild–II. Reassembly.

2017apr00-1With the master cylinder bore honed smooth, everything can be put together.  Thankfully, the brakes don’t need a jerry-rig to get back into shape; remarkably, Napa still makes and sells off-the-shelf rebuild kits for brake systems this old.  It was merely a matter of walking up to the counter and placing the order.  Had it in my hands the next morning; gotta love America and mass production—auto parts off the shelf.

Here is the content of the rebuild kit, laid out against the same parts from the disassembled cylinder assembly. To all appearances, the parts are identical.  I was more than a little surprised to note that the primary seal looks like it was even cast on the same mold, so maybe the brakes have been rebuilt at some point in the past more recent than “never.”

All but one of the parts—the spring, into which the valve assembly snaps—have a replacement part.  As mentioned, I want to use original equipment, reconditioning it if necessary, so the secondary seal came off the new piston and was put onto the original that I removed.  The old valve assembly snaps out of the spring and the new one snapped right into place.  One that was in place the innards were assembled as shown in the images.

Keep in mind that the piston and seals don’t just drop in place; they have to be pushed because they fit tightly into the bore.

Once the piston, seals, spring, and valve are in place the challenge becomes assembling the mechanical linkage. The pushrod assembly has a plate at one end that seals off the mechanical end of the master cylinder. The pushrod itself has an acorn head that engages the cupped end of the piston with the secondary seal.  Because the two pieces are not threaded or locked, the pushrod can turn and moves at a slight angle when the brake is engaged. That freedom of movement allows the pushrod to be turned with the knurled nut on the shaft allow it to be threaded into the fork on the brake shaft (today we’d probably just make the shaft hexagonal for a wrench). The boot threads over the knurled nut on the pushrod.  The round plate on the assembly fits into the end of the brake cylinder.  The snap ring holds it in place, and then the boot covers everything.  Won’t say how many times I took it apart because I missed something.

So here are before and after shots of the brake master cylinder, both taken as if looking at it from the driver’s side.  The plunger at the left is the link to the brake pedal (the fork visible in the “before” picture got removed and put back onto Green so I didn’t lose it).  The brake line itself threads into the cap on the right end.

Here is a section of the complete assembly from the shop manual, shown in working order for context.

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And that’s that.  Ready to go back onto the Green Truck.

Brake master cylinder rebuild–I. Honing.

Thanks to my patient reader (notice the use of the singular noun there) for not removing The Green Truck from your blog roll, despite the lag in substance this spring.  If there are more than one of you out there, well, great.  Hopefully action on the blog will pick up again.  This is a good place to start.

I talked about removing and disassembling the brake master cylinder in an earlier post.  This one continues the process in two parts:  the first one on reconditioning the bore, and a second one on reassembling the master cylinder (and hoping it is in working order).

Green rarely had servicing and what was services used to be fixed with baling wire (and yes, there are still pieces to be seen holding this or that together).  I’ve mentioned that there are absolutely no brakes–not a drop of brake fluid to be found in the lines.   Brakes are high on the list of necessaries on an automobile, so obviously something needed to be done.  I’ve been trying to find time to do this for six weeks, but I came home an hour early on a Friday afternoon and press-ganged Son Four into acting as a photographer so that I could document the work.

The bore of a brake master cylinder is normally smooth.  As you can see (below), the cylinder walls from Green’s cylinder are hardly smooth any more.  What has happened is that over time a tiny bit of moisture in the line has pitted the steel sides. That rust creates depressions that allows brake fluid to leak past the primary seal.  Pushing on the brake pedal becomes less effective because the hydraulics are compromised and don’t transfer the force effectively to the brake cylinders in the wheels.

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Pitting in the bore.

The brakes were failing as I drove Green in high school in the late 1970s and early 1980s. Thirty-five years of sitting in a field hasn’t helped.  To again function correctly the cylinder bore has to be smoothed out or replaced entirely.  Since I am trying to keep the original equipment on Green, the available options were fairly direct–the cylinder has to be honed smooth. Honing a cylinder is technologically simple but requires a specialized tool that would be used once and never again.  I still bought one.

A hone is nothing more than a trio of small grinding stones set on springs at the end of a shaft. Having three spring-loaded stones keeps them centered evenly against the bore walls as the shaft turns.

The challenge of honing a bore is to stay within tolerances:  just enough steel has to be removed to level the pits, but not so much that the primary and secondary seals no longer fit tightly.  After doing some exploring, the folks who have done this say that one aims at taking off no more than 0.004 of an inch, which enlarges the bore by twice that figure or 0.008 inches, because there is a bore wall on the opposite side as well.

Notice that the hone fits into a standard drill.  I could have maybe used a hand-operated eggbeater drill, but that would have been difficult to both hold and operate effectively.  As it was, I had to use both hands and compromised on the setup–I was supposed to use solvent to flush away the particulates from the grinding and prevent oxidation, but I followed DIY advice to use hot water, since I don’t have a shop solvent fountain.  Son Four did a thirty-second video of the hone in action, but my WordPress subscription does not allow me to post video files, so here are a couple of stills that show how it works.

 

After the bore was honed and while it was still wet, the cylinder went into the oven to dry it out quickly.  As it was there was still a film of oxidation (rust), which I wiped out first with a shop towel and then a bit of brake fluid to coat the steel and keep it from oxidizing again.

 

As you can see in comparing the two images, there are still a few shallow pits, but conventional wisdom is that something that small probably won’t affect the breaks much because the primary seal should be flexible enough to ride through them.

So, now all that needs to happen is to put everything back together.